Semiconductor System

ABSTRACT

To provide a semiconductor system including a plurality of core chips and an interface chip that controls the core chips. Each of the core chips includes an internal voltage generating circuit. The interface chip includes an unused chip information holding circuit that stores therein unused chip information of the core chips. The core chips respectively receive the unused chip information from the unused chip information holding circuit. When the unused chip information indicates an unused state, the internal voltage generating circuits are inactivated, and when the unused chip information indicates a used state, the internal voltage generating circuits are activated. With this configuration, unnecessary power consumption by the unused chips is reduced.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/964,796, filed Aug. 12, 2013, which is a continuation of U.S. patentapplication Ser. No. 13/595,793, filed Aug. 27, 2012, which is acontinuation of U.S. patent application Ser. No. 12/964,304, filed Dec.9, 2010, U.S. Pat. No. 8,274,847, which claims the priority of JapanesePatent Application No. 2009-281173, filed Dec. 11, 2009, the contents ofwhich prior applications are incorporated herein in their entirety byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor system, and moreparticularly relates to a semiconductor system including a plurality ofcontrolled chips and controlling chips that control the controlledchips.

2. Description of the Related Art

A memory capacity that is required in a semiconductor device such as adynamic random access memory (DRAM) has increased every year. In recentyears, a memory device that is called a multi-chip package where pluralmemory chips are laminated is suggested to satisfy the required memorycapacity. However, since the memory chip used in the multi-chip packageis a common memory chip capable of operating even though the memory chipis a single chip, a so-called front end unit that performs a function ofan interface with an external device (for example, memory controller) isincluded in each memory chip. For this reason, an area for a memory corein each memory chip is restricted to an area obtained by subtracting thearea for the front end unit from a total chip area, and it is difficultto greatly increase a memory capacity for each chip (for each memorychip).

In addition, a circuit that constitutes the front end unit ismanufactured at the same time as a back end unit including a memorycore, regardless of the circuit being a circuit of a logic system.Therefore there have been a further problem that it is difficult tospeed up the front end unit.

As a method to resolve the above problem, a method that integrates thefront end unit and the back end unit in individual chips and laminatesthese chips, thereby constituting one semiconductor device, is suggested(for example, Japanese Patent Application Laid-Open (JP-A) No.2007-157266). According to this method, with respect to plural corechips each of which is integrated with the back end unit without thefront end unit, it becomes possible to increase a memory capacity foreach chip (for each core chip) because an occupied area assignable forthe memory core increases. Meanwhile, with respect to an interface chipthat is integrated with the front end unit and is common to the pluralcore chips, it becomes possible to form its circuit with a high-speedtransistor because the interface chip can be manufactured using aprocess different from that of the memory core. In addition, since theplural core chips can be allocated to one interface chip, it becomespossible to provide a semiconductor device that has a large memorycapacity and a high operation speed as a whole.

However, this kind of semiconductor device is recognized as only onememory chip, in view of a controller. For this reason, when the pluralcore chips are allocated to one interface chip, how to perform anindividual access to each core chip becomes a problem. In the case ofthe general multi-chip package, each memory chip is individuallyselected using a dedicated chip selection terminal (/CS) in each memorychip. Meanwhile, in the semiconductor device described above, since thechip selection terminal is provided in only the interface chip, eachcore chip cannot be individually selected by a chip selection signal.

In order to resolve this problem, JP-A No. 2007-157266 described above,a chip identification number is allocated to each core chip, a chipselection address is commonly provided from the interface chip to eachcore chip, and individual selection of each core chip is realized.

In Japanese Patent Application Laid-open No. 2007-157266 discloses anarrangement in which core chips (DRAM chips) are stacked in five layers,an interface chip is stacked on the topmost layer of the core chips, andthese chips are connected to each other via through silicon vias. Toachieve such a chip-stacked semiconductor device, chips are individuallymanufactured, and are stacked and packaged after they are tested fordefects.

Sometimes defective core chips are found during checking afterassembling the chips. In this case, discarding the entire chip-stackedsemiconductor device is not always necessary because the remaining corechips and the interface chip are operating normally. There is a need ofa method for relieving normally functioning core chips by obtaining aso-called partial product in which the semiconductor device itself isnot considered as defective even though a portion of the core chips isdefective by operating only the normally functioning core chips withoutusing the defective core chips. Although not related to the chip-stackedsemiconductor device, techniques of using the so-called partial productare disclosed in Japanese Patent Application Laid-open Nos. H9-128995and H9-161997.

However, in the methods disclosed in Japanese Patent ApplicationLaid-open Nos. H9-128995 and H9-161497, an output of an internal voltagegenerating circuit is also supplied to an unused area. Therefore,unnecessarily power is consumed by the internal voltage generatingcircuit itself, and there is also a problem that a leakage current isproduced in the unused area. These problems are not limited tochip-stacked semiconductor devices, but also occur in a generalsemiconductor system including a plurality of controlled chips andcontrolling chips that control the controlled chips.

SUMMARY

In one embodiment, there is provided a semiconductor system thatincludes: a plurality of controlled chips each of which including aninternal voltage generating circuit; and a controlling chip thatcontrols the controlled chips, wherein the controlling chip includes anunused chip information holding circuit that stores therein unused chipinformation of the controlled chips, and each of the controlled chipsreceives corresponding one of the unused chip information from theunused chip information holding circuit, inactivates the internalvoltage generating circuit when the unused chip information indicates anunused state, and activates the internal voltage generating circuit whenthe unused chip information indicates a used state.

According to the present invention, because corresponding internalvoltage generating circuits are not activated in unused controlledchips, unnecessary power consumption by the internal voltage generatingcircuit itself is reduced, and a leakage current produced in the unusedcontrolled chips is also reduced. With this configuration, total powerconsumption of a semiconductor system can be reduced according to thenumber of unused controlled chips.

BRIEF DESCRIPTION OF THE DRAWINGS

The above features and advantages of the present invention will be moreapparent from the following description of certain preferred embodimentstaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic cross-sectional view showing the structure of asemiconductor device 10 according to the preferred embodiment of thepresent invention;

FIGS. 2A to 2C are diagram showing the various types of a throughsilicon via TSV provided in a core chip;

FIG. 3 is a cross-sectional view showing the structure of the throughsilicon via TSV1 of the type shown in FIG. 2A;

FIG. 4 is a block diagram showing the circuit configuration of thesemiconductor device 10;

FIG. 5 is a diagram showing in detail the elements related to internalvoltage generating circuits 40 and 70;

FIG. 6 is a circuit diagram of the internal voltage generating circuit70 d;

FIG. 7 is a circuit diagram of the internal voltage generating circuit70 b;

FIG. 8 is a waveform diagram showing an example of variations in aninternal voltage when the power is turned on;

FIG. 9 is a diagram showing circuits related to selection of the corechips CC0 to CC7;

FIG. 10 is a circuit diagram showing an example of a configuration ofthe layer address generating circuit 46;

FIG. 11 is a schematic diagram showing an example of allocations oflayer addresses when no defective chip exists;

FIG. 12 is a schematic diagram showing an example of allocations oflayer addresses when defective chips exist;

FIG. 13 is a schematic diagram showing another example of allocations oflayer addresses when defective chips exist;

FIG. 14 is a circuit diagram showing a configuration of the layeraddress comparing circuit 47;

FIG. 15A is a diagram showing a configuration of a semiconductor system200; and

FIG. 15B is a diagram showing a configuration of a semiconductor system300.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will be explained belowin detail with reference to the accompanying drawings.

FIG. 1 is a schematic cross-sectional view provided to explain thestructure of a semiconductor memory device 10 according to the preferredembodiment of the present invention.

As shown in FIG. 1, the semiconductor memory device 10 according to thisembodiment has the structure where 8 core chips CC0 to CC7 that have thesame function and structure and are manufactured using the samemanufacture mask, an interface chip IF that is manufactured using amanufacture mask different from that of the core chips and an interposerIP are laminated. The core chips CC0 to CC7 and the interface chip IFare semiconductor chips using a silicon substrate and are electricallyconnected to adjacent chips in a vertical direction through pluralThrough Silicon Vias (TSV) penetrating the silicon substrate. Meanwhile,the interposer IP is a circuit board that is made of a resin, and pluralexternal terminals (solder balls) SB are formed in a back surface IPb ofthe interposer IF.

Each of the core chips CC0 to CC7 is a semiconductor chip which consistsof circuit blocks other than a so-called front end unit (front endfunction) performing a function of an interface with an external devicethrough an external terminal among circuit blocks included in a 1 GbDDR3 (Double Data Rate 3)-type SDRAM (Synchronous Dynamic Random AccessMemory). The SDRAM is a well-known and common memory chip that includesthe front end unit and a so-called back end unit having a plural memorycells and accessing to the memory cells. The SDRAM operates even as asingle chip and is capable to communicate directly with a memorycontroller. That is, each of the core chips CC0 to CC7 is asemiconductor chip where only the circuit blocks belonging to the backend unit are integrated in principle. As the circuit blocks that areincluded in the front end unit, a parallel-serial converting circuit(data latch circuit) that performs parallel/serial conversion oninput/output data between a memory cell array and a data input/outputterminal and a DLL (Delay Locked Loop) circuit that controlsinput/output timing of data are exemplified, which will be described indetail below. The interface chip IF is a semiconductor chip in whichonly the front end unit is integrated. Accordingly, an operationfrequency of the interface chip is higher than an operation frequency ofthe core chip. Since the circuits that belong to the front end unit arenot included in the core chips CC0 to CC7, the core chips CC0 to CC7cannot be operated as the single chips, except for when the core chipsare operated in a wafer state for a test operation in the course ofmanufacturing the core chips. The interface chip IF is needed to operatethe core chips CC0 to CC7. Accordingly, the memory integration of thecore chips is denser than the memory integration of a general singlechip. In the semiconductor memory device 10 according to thisembodiment, the interface chip has a front end function forcommunicating with the external device at a first operation frequency,and the plural core chips have a back end function for communicatingwith only the interface chip at a second operation frequency lower thanthe first operation frequency. Accordingly, each of the plural corechips includes a memory cell array that stores plural information, and abit number of plural read data for each I/O (DQ) that are supplied fromthe plural core chips to the interface chip in parallel is plural andassociated with a one-time read command provided from the interface chipto the core chips. In this case, the plural bit number corresponds to aprefetch data number to be well-known.

The interface chip IF functions as a common front end unit for the eightcore chips CC0 to CC7. Accordingly, all external accesses are performedthrough the interface chip IF and inputs/outputs of data are alsoperformed through the interface chip IF. In this embodiment, theinterface chip IF is disposed between the interposer IP and the corechips CC0 to CC7. However, the position of the interface chip IF is notrestricted in particular, and the interface chip IF may be disposed onthe core chips CC0 to CC7 and may be disposed on the back surface IPb ofthe interposer IP. When the interface chip IF is disposed on the corechips CC0 to CC7 in a face-down manner or is disposed on the backsurface IPb of the interposer IP in a face-up manner, the throughsilicon via TSV does not need to be provided in the interface chip IF.The interface chip IF may be disposed to be interposed between the twointerposers IP.

The interposer IP functions as a rewiring substrate to increase anelectrode pitch and secures mechanical strength of the semiconductormemory device 10. That is, an electrode 91 that is formed on a topsurface IPa of the interposer IP is drawn to the back surface IPb via athrough-hole electrode 92 and the pitch of the external terminals SB isenlarged by the rewiring layer 93 provided on the back surface IPb. InFIG. 1, only the two external terminals SB are shown. In actuality,however, three or more external terminals are provided. The layout ofthe external terminals SB is the same as that of the DDR3-type SDRAMthat is determined by the regulation. Accordingly, the semiconductormemory device can be treated as one DDR3-type SDRAM from the externalcontroller.

As shown in FIG. 1, a top surface of the uppermost core chip CC0 iscovered by an NCF (Non-Conductive Film) 94 and a lead frame 95. Gapsbetween the core chips CC0 to CC7 and the interface chip IF are filledwith an underfill 96 and surrounding portions of the gaps are covered bya sealing resin 97. Thereby, the individual chips are physicallyprotected.

When most of the through silicon vias TSV provided in the core chips CC0to CC7 are two-dimensionally viewed from a lamination direction, thatis, viewed from an arrow A shown in FIG. 1, the through silicon vias TSVare short-circuited from the through silicon vias TSV of other layersprovided at the same position. That is, as shown in FIG. 2A, thevertically disposed through silicon vias TSV1 that are provided at thesame position in plain view are short-circuited, and one wiring line isconfigured by the through silicon via TSV1. The through silicon via TSV1that are provided in the core chips CC0 to CC7 are connected to internalcircuits 4 in the core chips, respectively. Accordingly, input signals(command signal, address signal, etc.) that are supplied from theinterface chip IF to the through silicon vias TSV1 shown in FIG. 2A arecommonly input to the internal circuits 4 of the core chips CC0 to CC7.Output signals (data etc.) that are supplied from the core chips CC0 toCC7 to the through silicon via TSV1 are wired-ORed and input to theinterface chip IF.

Meanwhile, as shown in FIG. 2B, the a part of through silicon vias TSVare not directly connected to the through silicon via TSV2 of otherlayers provided at the same position in plain view but are connected tothe through silicon via TSV2 of other layers through the internalcircuits 5 provided in the core chips CC0 to CC7. That is, the internalcircuits 5 that are provided in the core chips CC0 to CC7 arecascade-connected through the through silicon via TSV2. This kind ofthrough silicon via TSV2 is used to sequentially transmit predeterminedinformation to the internal circuits 5 provided in the core chips CC0 toCC7. As this information, layer address information to be describedbelow is exemplified.

Another through silicon via group is short-circuited from the throughsilicon vias TSV of other layer provided at the different position inplan view, as shown in FIG. 2C. With respect to this kind of throughsilicon via group 3, internal circuits 6 of the core chips CC0 to CC7are connected to the through silicon via TSV3a provided at thepredetermined position P in plain view. Thereby, information can beselectively input to the internal circuits 6 provided in the core chips.As this information, defective chip information to be described below isexemplified.

As such, as types of the through silicon vias TSV provided in the corechips CC0 to CC7, three types (through silicon via TSV1 to throughsilicon via TSV3) shown in FIGS. 2A to 2C exist. As described above,most of the Through silicon vias TSV are of a type shown in FIG. 2A, andan address signal, a command signal, and a clock signal are suppliedfrom the interface chip IF to the core chips CC0 to CC7, through thethrough silicon via TSV1 of the type shown in FIG. 2A. Read data andwrite data are input to and output from the interface chip IF throughthe through silicon via TSV1 of the type shown in FIG. 2A. Meanwhile,the through silicon via TSV2 and through silicon via TSV3 of the typesshown in FIGS. 2B and 2C are used to provide individual information tothe core chips CC0 to CC7 having the same structure.

FIG. 3 is a cross-sectional view showing the structure of the throughsilicon via TSV1 of the type shown in FIG. 2A.

As shown in FIG. 3, the through silicon via TSV1 is provided topenetrate a silicon substrate 80 and an interlayer insulating film 81provided on a surface of the silicon substrate 80. Around the throughsilicon via TSV1, an insulating ring 82 is provided. Thereby, thethrough silicon via TSV1 and a transistor region are insulated from eachother. In an example shown in FIG. 3, the insulating ring 82 is provideddouble. Thereby, capacitance between the through silicon via TSV1 andthe silicon substrate 80 is reduced.

An end 83 of the through silicon via TSV1 at the back surface of thesilicon substrate 80 is covered by a back surface bump 84. The backsurface bump 84 is an electrode that contacts a surface bump 85 providedin a core chip of a lower layer. The surface bump 85 is connected to anend 86 of the through silicon via TSV1, through plural pads P0 to P3provided in wiring layers L0 to L3 and plural through-hole electrodesTH1 to TH3 connecting the pads to each other. Thereby, the surface bump85 and the back surface bump 84 that are provided at the same positionin plain view are short-circuited. Connection with internal circuits(not shown in the drawings) is performed through internal wiring lines(not shown in the drawings) drawn from the pads P0 to P3 provided in thewiring layers L0 to L3.

FIG. 4 is a block diagram showing the circuit configuration of thesemiconductor memory device 10.

As shown in FIG. 4, the external terminals that are provided in theinterposer IP include clock terminals 11 a and 11 b, an clock enableterminal 11 c, command terminals 12 a to 12 e, an address terminal 13, adata input/output terminal 14, data strobe terminals 15 a and 15 b, acalibration terminal 16, and power supply terminals 17 a and 17 b. Allof the external terminals are connected to the interface chip IF and arenot directly connected to the core chips CC0 to CC7, except for thepower supply terminals 17 a and 17 b.

First, a connection relationship between the external terminals and theinterface chip IF performing the front end function and the circuitconfiguration of the interface chip IF will be described.

The clock terminals 11 a and 11 b are supplied with external clocksignals CK and /CK, respectively, and the clock enable terminal 11 c issupplied with a clock enable signal CKE. The external clock signals CKand /CK and the clock enable signal CKE are supplied to a clockgenerating circuit 21 provided in the interface chip IF. A signal where“/” is added to a head of a signal name in this specification indicatesan inversion signal of a corresponding signal or a low-active signal.Accordingly, the external clock signals CK and /CK are complementarysignals. The clock generating circuit 21 generates an internal clocksignal ICLK, and the generated internal clock signal ICLK is supplied tovarious circuit blocks in the interface chip IF and is commonly suppliedto the core chips CC0 to CC7 through the through silicon vias TSV.

A DLL circuit 22 is included in the interface chip IF and aninput/output clock signal LCLK is generated by the DLL circuit 22. Theinput/output clock signal LCLK is supplied to an input/output buffercircuit 23 included in the interface chip IF. A DLL function is used tocontrol the front end unit by using the signal LCLK synchronized with asignal of the external device, when the semiconductor memory device 10communicates with the external device. Accordingly, DLL function is notneeded for the core chips CC0 to CC7 as the back end.

The command terminals 12 a to 12 e are supplied with a row-addressstrobe signal /RAS, a column address strobe signal /CAS, a write enablesignal /WE, a chip select signal /CS, and an on-die termination signalODT. These command signals are supplied to a command input buffer 31that is provided in the interface chip IF. The command signals suppliedto the command input buffer 31 are further supplied to a command decoder32. The command decoder 32 is a circuit that holds, decodes, and countsthe command signals in synchronization with the internal clock ICLK andgenerates various internal commands ICMD. The generated internal commandICMD is supplied to the various circuit blocks in the interface chip IFand is commonly supplied to the core chips CC0 to CC7 through thethrough silicon vias TSV.

The address terminal 13 is a terminal to which address signals A0 to A15and BA0 to BA2 are supplied, and the supplied address signals A0 to A15and BA0 to BA2 are supplied to an address input buffer 41 provided inthe interface chip IF. An output of the address input buffer 41 iscommonly supplied to the core chips CC0 to CC7 through the throughsilicon vias TSV. The address signals A0 to A15 are supplied to a moderegister 42 provided in the interface chip IF, when the semiconductormemory device 10 enters a mode register set. The address signals BA0 toBA2 (bank addresses) are decoded by an address decoder (not shown in thedrawings) provided in the interface chip IF, and a bank selection signalB that is obtained by the decoding is supplied to a data latch circuit25. This is because bank selection of the write data is performed in theinterface chip IF.

The data input/output terminal 14 is used to input/output read data orwrite data DQ0 to DQ15. The data strobe terminals 15 a and 15 b areterminals that are used to input/output strobe signals DQS and /DQS. Thedata input/output terminal 14 and the data strobe terminals 15 a and 15b are connected to the input/output buffer circuit 23 provided in theinterface chip IF. The input/output buffer circuit 23 includes an inputbuffer IB and an output buffer OB, and inputs/outputs the read data orthe write data DQ0 to DQ15 and the strobe signals DOS and /DQS insynchronization with the input/output clock signal. LCLK supplied fromthe DLL circuit 22. If an internal on-die termination signal IODT issupplied from the command decoder 32, the input/output buffer circuit 23causes the output buffer OB to function as a termination resistor. Animpedance code DRZQ is supplied from the calibration circuit 24 to theinput/output buffer circuit 23. Thereby, impedance of the output bufferOB is designated. The input/output buffer circuit 23 includes awell-known FIFO circuit.

The calibration circuit 24 includes a replica buffer RB that has thesame circuit configuration as the output buffer OB. If the calibrationsignal ZQ is supplied from the command decoder 32, the calibrationcircuit 24 refers to a resistance value of an external resistor (notshown in the drawings) connected to the calibration terminal 16 andperforms a calibration operation. The calibration operation is anoperation for matching the impedance of the replica buffer RB with theresistance value of the external resistor, and the obtained impedancecode DRZQ is supplied to the input/output buffer circuit 23. Thereby,the impedance of the output buffer OB is adjusted to a desired value.

The input/output buffer circuit 23 is connected to a data latch circuit25. The data latch circuit 25 includes a FIFO circuit (not shown in thedrawings) that realizes a FIFO function which operates by latencycontrol realizing the well-known DDR function and a multiplexer MUX (notshown in the drawings). The input/output buffer circuit 23 convertsparallel read data, which is supplied from the core chips CC0 to CC7,into serial read data, and converts serial write data, which is suppliedfrom the input/output buffer, into parallel write data. Accordingly, thedata latch circuit 25 and the input/output buffer circuit 23 areconnected in serial and the data latch circuit 25 and the core chips CC0to CC7 are connected in parallel. In this embodiment, each of the corechips CC0 to CC7 is the back end unit of the DDR3-type SDRAM and aprefetch number is 8 bits. The data latch circuit 25 and each banks ofthe core chips CC0 to CC7 are connected respectively, and the number ofbanks that are included in each of the core chips CC0 to CC7 is 8.Accordingly, connection of the data latch circuit 25 and the core chipsCC0 to CC7 becomes 64 bits (8 bits×8 banks) for each DQ.

Parallel data, not converted into serial data, is basically transferredbetween the data latch circuit 25 and the core chips CC0 to CC7. Thatis, in a common SDRAM (in the SDRAM, a front end unit and a back endunit are constructed in one chip), between the outside of the chip andthe SDRAM, data is input/output in serial (that is, the number of datainput/output terminals is one for each DQ). However, in the core chipsCC0 to CC7, an input/output of data between the interface chip IF andthe core chips is performed in parallel. This point is the importantdifference between the common SDRAM and the core chips CC0 to CC7. Inother words, the number of bits of unit internal data simultaneouslyinput and output between the core chips CC0 to CC7 and the interfacechip IF is greater than the number of bits of unit external datasimultaneously input and output between the interface chip IF andoutside. However, all of the prefetched parallel data do not need to beinput/output using the different through silicon vias TSV, and partialparallel/serial conversion may be performed in the core chips CC0 to CC7and the number of through silicon vias TSV that are needed for each DQmay be reduced. For example, all of data of 64 bits for each DQ do notneed to be input/output using the different through silicon vias TSV,and 2-bit parallel/serial conversion may be performed in the core chipsCC0 to CC7 and the number of through silicon vias TSV that are neededfor each DQ may be reduced to ½ (32).

To the data latch circuit 25, a function for enabling a test in aninterface chip unit is added. The interface chip does not have the backend unit. For this reason, the interface chip cannot be operated as asingle chip in principle. However, if the interface chip never operatesas the single chip, an operation test of the interface chip in a waferstate may not be performed. This means that the semiconductor memorydevice 10 cannot be tested in case an assembly process of the interfacechip and the plural core chips is not executed, and the interface chipis tested by testing the semiconductor memory device 10. In this case,when a defect that cannot be recovered exists in the interface chip, theentire semiconductor memory device 10 is not available. In considerationof this point, in this embodiment, a portion of a pseudo back end unitfor a test is provided in the data latch circuit 25, and a simple memoryfunction is enabled at the time of a test.

The power supply terminals 17 a and 17 b are terminals to which powersupply potentials VDD and VSS are supplied, respectively. The powersupply terminals 17 a and 17 b are connected to a power-on detectingcircuit 43 provided in the interface chip IF and are also connected tothe core chips CC0 to CC7 through the through silicon vias TSV. Thepower-on detecting circuit 43 detects the supply of power. On detectingthe supply of power, the power-on detecting circuit 43 activates a layeraddress control circuit 45 on the interface chip IF.

The layer address control circuit 45 changes a layer address due to theI/O configuration of the semiconductor device 10 according to thepresent embodiment. As described above, the semiconductor memory device10 includes 16 data input/output terminals 14. Thereby, a maximum I/Onumber can be set to 16 bits (DQ0 to DQ15). However, the I/O number isnot fixed to 16 bits and may be set to 8 bits (DQ0 to DQ7) or 4 bits(DQ0 to DQ3). The address allocation is changed according to the I/Onumber and the layer address is also changed. The layer address controlcircuit 45 changes the address allocation according to the I/O numberand is commonly connected to the core chips CC0 to CC7 through thethrough silicon vias TSV.

The interface chip IF is also provided with a layer address settingcircuit 44. The layer address setting circuit 44 is connected to thecore chips CC0 to CC7 through the through silicon vias TSV. The layeraddress setting circuit 44 is cascade-connected to the layer addressgenerating circuit 46 of the core chips CC0 to CC7 using the throughsilicon via TSV2 of the type shown in FIG. 2B, and reads out the layeraddresses set to the core chips CC0 to CC7 at testing.

The interface chip IF is also provided with an unused chip informationholding circuit 33. When a defective core chip that does not normallyoperates is discovered after an assembly, the unused chip informationholding circuit 33 holds its chip number. The defective chip informationholding circuit 33 is connected to the core chips CC0 to CC7 through thethrough silicon vias TSV. The defective chip information holding circuit33 is connected to the core chips CC0 to CC7 while being shifted, usingthe through silicon via TSV3 of the type shown in FIG. 2C.

The above description is the outline of the connection relationshipbetween the external terminals and the interface chip IF and the circuitconfiguration of the interface chip IF. Next, the circuit configurationof the core chips CC0 to CC7 will be described.

As shown in FIG. 4, memory cell arrays 50 that are included in the corechips CC0 to CC7 performing the back end function are divided into eightbanks. A bank is a unit that can individually receive a command. Thatis, the individual banks can be independently and nonexclusivelycontrolled. From the outside of the semiconductor memory device 10, eachback can be independently accessed. For example, a part of the memorycell array 50 belonging to the bank 1 and another part of the memorycell array 50 belonging to the bank 2 are controlled nonexclusively.That is, word lines WL and bit lines BL corresponding to each banksrespectively are independently accessed at same period by differentcommands one another. For example, while the bank 1 is maintained to beactive (the word lines and the bit lines are controlled to be active),the bank 2 can be controlled to be active. However, the externalterminals (for example, plural control terminals and plural I/Oterminals) of the semiconductor memory device 10 are shared. In thememory cell array 50, the plural word lines WL and the plural bit linesBL intersect each other, and memory cells MC are disposed atintersections thereof (in FIG. 4, only one word line WL, one bit lineBL, and one memory cell MC are shown). The word line WL is selected by arow decoder 51. The bit line BL is connected to a corresponding senseamplifier SA in a sense circuit 53. The sense amplifier SA is selectedby a column decoder 52.

The row decoder 51 is controlled by a row address supplied from a rowcontrol circuit 61. The row control circuit 61 includes an addressbuffer 61 a that receives a row address supplied from the interface chipIF through the through silicon via TSV, and the row address that isbuffered by the address buffer 61 a is supplied to the row decoder 51.The address signal that is supplied through the through silicon via TSVis supplied to the row control circuit 61 through the input buffer B1.The row control circuit 61 also includes a refresh counter 61 b. When arefresh signal is issued by a control logic circuit 63, a row addressthat is indicated by the refresh counter 61 b is supplied to the rowdecoder 51.

The column decoder 52 is controlled by a column address supplied from acolumn control circuit 62. The column control circuit 62 includes anaddress buffer 62 a that receives the column address supplied from theinterface chip IF through the through silicon via TSV, and the columnaddress that is buffered by the address buffer 62 a is supplied to thecolumn decoder 52. The column control circuit 62 also includes a burstcounter 62 b that counts the burst length.

The sense amplifier SA selected by the column decoder 52 is connected tothe data control circuit 54 through some amplifiers (sub-amplifiers ordata amplifiers or the like) which are not shown in the drawings.Thereby, read data of 8 bits (=prefetch number) for each I/O (DQ) isoutput from the data control circuit 54 at reading, and write data of 8bits is input to the data control, circuit 54 at writing. The datacontrol circuit 54 and the interface chip IF are connected in parallelthrough the through silicon via TSV.

The control logic circuit 63 receives an internal command ICMD suppliedfrom the interface chip IF through the through silicon via TSV andcontrols the row control circuit 61 and the column control circuit 62,based on the internal command ICMD. The control logic circuit 63 isconnected to a layer address comparing circuit (chip address comparingcircuit) 47. The layer address comparing circuit 47 detects whether thecorresponding core chip is target of access, and the detection isperformed by comparing a SEL (chip selection information/third chipaddress) which is a part of the address signal supplied from theinterface chip IF through the through silicon via TSV and a layeraddress LID (chip identification information/second chip address) set tothe layer address generating circuit 46.

In the layer address generating circuit (chip second chip addressgenerating circuit) 46, unique layer addresses are set to the core chipsCC0 to CC7, respectively, at initialization. A method of setting thelayer addresses is as follows. First, after the semiconductor memorydevice 10 is initialized, a minimum value (0, 0, 0) as an initial valueis set to the layer address generating circuits 46 of the core chips CC0to CC7. The layer address generating circuits 46 of the core chips CC0to CC7 are cascade-connected using the through silicon vias TSV of thetype shown in FIG. 28, and have incrementing circuits provided therein.The layer address (0, 0, 0) that is set to the layer address generatingcircuit 46 of the core chip CC0 of the uppermost layer is transmitted tothe layer address generating circuit 46 of the second core chip CC1through the through silicon via TSV and is incremented. As a result, adifferent layer address (0, 0, 1) is generated. Hereinafter, in the sameway as the above case, the generated layer addresses are transmitted tothe core chips of the lower layers and the layer address generatingcircuits 46 in the core chips increment the transmitted layer addresses.A maximum value (1, 1, 1) as a layer address is set to the layer addressgenerating circuit 46 of the core chip CC7 of the lowermost layer.Thereby, the unique layer addresses are set to the core chips CC0 toCC7, respectively.

The layer address generating circuit 46 is provided with a unused chipsignal DEF supplied from the unused chip information holding circuit 33of the interface chip IF, through the through silicon via TSV. As theunused chip signal DEF is supplied to the individual core chips CC0 toCC7 using the through silicon via TSV3 of the type shown in FIG. 2C, theunused chip signals DEF can be supplied to the core chips CC0 to CC7,individually. The unused chip signal DEF is activated when thecorresponding core chip is a defective chip. When the unused chip signalDEF is activated, the layer address generating circuit 46 transmits, tothe core chip of the lower layer, a non-incremented layer address, notan incremented layer address. The unused chip signal DEF is alsosupplied to the layer address comparing circuit 47. When the unused chipsignal DEF is in an active state, a comparison result of the layeraddresses is forcibly set to a mismatch. An output of the layer addresscomparing circuit 47 is supplied to the control logic circuit 63.However, the control logic circuit 63 is not activated if a coincidencesignal is not output. Consequently, when the comparison result indicatesa mismatch, the control logic circuit 63 is stopped. Thereby, thedefective core chip performs neither read operation nor write operation,even though an address signal or a command signal is input from theinterface chip IF.

A partial signal is also supplied to the layer address comparing circuit47 via the through silicon via TSV1. The partial signal is supplied fromthe unused chip information holding circuit 33. However, a dedicatedcircuit that supplies the partial signal can be provided. The partialsignal is supplied to all the core chips CC0 to CC7 via the throughsilicon via TSV1 of the type shown in FIG. 2A, and thus a common partialsignal can be supplied to all the core chips CC0 to CC7. The partialsignal is a signal that is activated when the semiconductor device 10 isused as a partial product due to at least one of the core chips CC0 toCC7 being defective. When the partial signal is active, the number ofbits of the layer addresses compared by the layer address comparingcircuit 47 is changed to two, that is, the number of layer addresses ischanged to that corresponding to the partial product.

An output of the control logic circuit 63 is also supplied to a moderegister 64. When an output of the control logic circuit 63 shows a moderegister set, the mode register 64 is updated by an address signal.Thereby, operation modes of the core chips CC0 to CC7 are set.

Each of the core chips CC0 to CC7 has an internal voltage generatingcircuit 70. The internal voltage generating circuit 70 is provided withpower supply potentials VDD and VSS. The internal voltage generatingcircuit 70 receives these power supply potentials and generates variousinternal voltages. As the internal, voltages that are generated by theinternal voltage generating circuit 70, an internal voltage VPERI (˜VDD)for operation power of various peripheral circuits, an internal voltageVARY (<VDD) for an array voltage of the memory cell array 50, and aninternal voltage VPP (>VDD) for an activation potential of the word lineWL are included. Details of the internal voltage generating circuit 70are described later. In each of the core chips CC0 to CC7, a power-ondetecting circuit 71 is also provided. When the supply of power isdetected, the power-on detecting circuit 71 resets various internalcircuits.

The peripheral circuits in the core chips CC0 to CC7 operates insynchronization with the internal clock signal ICLK that is suppliedform the interface chip IF through the through silicon via TSV. Theinternal clock signal ICLK supplied through the through silicon via TSVis supplied to the various peripheral circuits through the input buffer82.

The above description is the basic circuit configuration of the corechips CC0 to CC7. In the core chips CC0 to CC7, the front end unit foran interface with the external device is not provided. Therefore thecore chip cannot operate as a single chip in principle. However, if thecore chip never operates as the single chip, an operation test of thecore chip in a wafer state may not be performed. This means that thesemiconductor memory device 10 cannot be tested, before the interfacechip and the plural core chips are fully assembled. In other words, theindividual core chips are tested when testing the semiconductor memorydevice 10. When unrecoverable defect exists in the core chips, theentire semiconductor memory device 10 is led to be unavailable. In thisembodiment, in the core chips CC0 to CC7, a portion of a pseudo frontend unit, for testing, that includes some test pads TP and a test frontend unit of a test command decoder 65 is provided, and an address signaland test data or a command signal, can be input from the test pads TP.It is noted that the test front end unit is provided for a simple testin a wafer test, and does not have all of the front end functions in theinterface chip. For example, since an operation frequency of the corechips is lower than an operation frequency of the front end unit, thetest front end unit can be simply realized with a circuit that performsa test with a low frequency.

Kinds of the test pads TP are almost the same as those of the externalterminals provided in the interposer IP. Specifically, the test padsinclude a test pad TP1 to which a clock signal is input, a test pad TP2to which an address signal is input, a test pad TP3 to which a commandsignal is input, a test pad TP4 for input/output test data, a test padTP5 for input/output a data strobe signal, and a test pad TP6 for apower supply potential.

A common external command (not decoded) is input at testing. Therefore,the test command decoder 65 is also provided in each of the core chipsCC0 to CC7. Because serial test data is input and output at testing, atest input/output circuit 55 is also provided in each of the core chipsCC0 to CC7.

This is the entire configuration of the semiconductor memory device 10.Because in the semiconductor memory device 10, the 8 core chips of 1 Gbare laminated, the semiconductor memory device 10 has a memory capacityof 8 Gb in total. Because the chip selection signal /CS is input to oneterminal (chip selection terminal), the semiconductor memory device isrecognized as a single DRAM having the memory capacity of 8 Gb, in viewof the controller.

FIG. 5 is a diagram showing in detail the elements related to theinternal voltage generating circuits 40 and 70 in the semiconductordevice 10 according to the present embodiment.

As shown in FIG. 5, the internal voltage generating circuit 40 providedin the interface chip IF includes an internal voltage generating circuit40 a that generates an internal voltage VPERI and an internal voltagegenerating circuit 40 b that generates an internal voltage VPP. Theinternal voltage VPERI is an internal voltage used as an operatingvoltage of almost all circuits in the interface chip IF. In the presentembodiment, VPERI is set approximately equal to VDD. On the other hand,the internal voltage VPP is an internal voltage obtained by boosting theexternal voltage VDD (VPP>VDD) and it is supplied to a boost circuit 40c. The boost circuit 40 c is a circuit that generates a super voltageSVT by further boosting the internal voltage VPP. The generated supervoltage SVT (>VPP) is supplied to the unused chip information holdingcircuit 33.

The unused chip information holding circuit 33 includes a fuse circuitunit 33 a and a logic circuit unit 33 b. The super voltage SVT is usedas a write voltage for writing to the fuse circuit unit 33 a.Information written to the fuse circuit unit 33 a is the unused chipsignal DEF that indicates a defective core chip detected after assembly.The information is written to the fuse circuit unit 33 a during anoperation test after assembly. The internal voltage VPP is generatedwhen a test signal TEST is activated during the operation test andsupplied to the internal voltage generating circuit 40 b. Thus, theinternal voltage VPP is not generated and almost no power is consumed bythe internal voltage generating circuit 40 b during a normal operation.

The unused chip signal DEF written to the fuse circuit unit 33 a issupplied to corresponding core chips CC0 to CC7 via the logic circuitunit 33 b and the through silicon via TSV3 of the type shown in FIG. 2C.Because the unused chip signal DEF is supplied to each of the core chipsCC0 to CC7 via the through silicon via TSV3 of the type shown in FIG.2C, individual unused chip signals DEF0 to DEF7 are supplied to each ofthe core chips CC0 to CC7. When fuse elements are used corresponding toeach of the unused chip signals DEF0 to DEF7, the same unused chipsignals DEF0 to DEF7 are output from the fuse circuit unit 33 a.Therefore, in this case, the logic circuit unit 33 b can be omitted.

As shown in FIG. 5, the internal voltage generating circuit 70 arrangedin the core chips CC0 to CC7 includes internal voltage generatingcircuits 70 a and 70 b that generate the internal voltage VPERI, aninternal voltage generating circuit 70 c that generates the internalvoltage VPP, and an internal voltage generating circuit 70 d thatgenerates the internal voltage VARY. As described earlier, the internalvoltage VPERI is an internal voltage used as an operating power for thevarious peripheral circuits, the internal voltage VPP is a drivingvoltage of the word line WL, and the internal voltage VARY is the arrayvoltage of the memory cell array 50. The internal voltages VPERIgenerated by both the internal voltage generating circuits 70 a and 70 bhave the same voltage level: however, an output of the internal voltagegenerating circuit 70 a is denoted as VPERIa when it is necessary todifferentiate between the two.

The internal voltage generating circuits 70 a to 70 d are circuits thatreceive the external voltage VDD and an external voltage GND suppliedfrom the interface chip IF via the through silicon via TSV1 and generatethe relevant internal voltages. The generated internal voltages are usedonly within the respective core chips CC0 to CC7. That is, the internalvoltages generated in the core chips CC0 to CC7 are electricallyseparated from each other and they are not shared among a plurality ofcore chips.

The internal voltage generating circuit 70 a is a circuit that suppliesthe internal voltage VPERI to the layer address generating circuit 46and a buffer B3, and it is activated whenever the power is turned on.The layer address generating circuit 46 is a circuit that generates alayer address of the respective core chips CC0 to CC7, and the buffer B3is a circuit that performs buffering of the unused chip signal DEFsupplied via the through silicon via TSV3 and supplies the unused chipsignal DEF to the layer address generating circuit 46. Because the layeraddress generating circuit 46 and the buffer B3 have to performoperations regardless of whether the core chips CC0 to CC7 aredefective, the internal voltage generating circuit 70 a always suppliesthe internal voltage VPERI to the layer address generating circuit 46and the buffer B3.

On the other hand, the internal voltage generating circuits 70 b to 70 dare activated or not activated depending on the corresponding unusedchip signal DEF. Specifically, when the unused chip signal DEF indicatesan unused state of the core chips CC0 to CC7 (when the unused chipsignal DEF is active), the internal voltage generating circuits 70 b to70 d are not activated. Conversely, when the unused chip signal DEFindicates a used state of the core chips CC0 to CC7 (when the unusedchip signal DEF is inactive), the internal voltage generating circuits70 b to 70 d are activated. Thus, in the core chips CC0 to CC7 for whichthe unused chip signal DEF is active, the operating power is notsupplied to circuits such as the memory cell array 50, the row decoder51, the column decoder 52, and a sense circuit 53, that is, the circuitsexcluding the layer address generating circuit 46 and the buffer 83.Outputs of the internal voltage generating circuits 70 b to 70 d thatare inactive are fixed to a ground level.

FIG. 6 is a circuit diagram of the internal voltage generating circuit70 d.

The internal voltage generating circuit 70 d shown in FIG. 6 includes aresistance dividing circuit 100 that generates a reference potentialVREF1, a differential circuit 110 that receives the reference potentialVREF1, and an N-channel driver transistor 120 that generates theinternal voltage VARY depending on an output of the differential circuit110. A P-channel MOS transistor 131 is connected to the resistancedividing circuit 100 in series and the unused chip signal DEF issupplied to a gate electrode of the P-channel MOS transistor 131. Alogic circuit including an inverter 132 and an AND gate 133 is providedbetween the differential circuit 110 and the driver transistor 120.Furthermore, an N-channel MOS transistor 134 is connected between anoutput terminal of the driver transistor 120 and ground and the unusedchip signal DEF is supplied to a gate electrode of the N-channel MOStransistor 134.

With this configuration, when the unused chip signal DEF is at a lowlevel (an inactive state), the transistor 131 is turned on and thetransistor 134 is turned off. Moreover, because a gate signal of thedriver transistor 120 is not interrupted due to the AND gate 133, theinternal voltage generating circuit 70 d generates the internal voltageVARY. On the other hand, when the unused chip signal DEF is at a highlevel (an active state), the transistor 131 is turned off and thetransistor 134 is turned on. Moreover, because an output of the AND gate133 is maintained at a low level, the operation of the internal voltagegenerating circuit 70 d is stopped and the output of the internalvoltage generating circuit 70 d is fixed to the ground level. As aresult, almost no power is consumed by the internal voltage generatingcircuit 70 d apart from a slight leakage current. Furthermore, becausethe power is also not supplied to circuits (the memory cell array 50 andthe like) using the internal voltage VARY, the power consumption bythese circuits is almost zero. That is, because a substrate potential, asource, and a drain of each of all the elements in the circuits that usethe internal voltage VARY are all at the ground level, none of theseelements produce the leakage current. The internal voltage generatingcircuit 70 d is the only circuit that releases the leakage current.However, because the number of elements and a size of the internalvoltage generating circuit 70 d are restricted considerably as comparedto all the elements using the internal voltage VARY, the effect on thereduction of the leakage current is significant.

FIG. 7 is a circuit diagram of the internal voltage generating circuit70 b.

The internal voltage generating circuit 70 b shown in FIG. 7 includes alevel conversion circuit 140 that converts a level of the unused chipsignal DEF to a VPP level, an N-channel driver transistor 141 thatgenerates the internal voltage VPERI depending on an output of the levelconversion circuit 140, and an N-channel MOS transistor 142 connectedbetween an output terminal of the driver transistor 141 and ground. InFIG. 7, a transistor with a thick gate electrode signifies a highvoltage transistor having a relatively thick gate insulation film.

With this configuration, when the unused chip signal DEF is at a lowlevel (an inactive state), because the transistor 141 is turned on andthe transistor 142 is turned off, the internal voltage generatingcircuit 70 b generates the internal voltage VPERI. On the other hand,when the unused chip signal DEF is at a high level (an active state),because the transistor 141 is turned off and the transistor 142 isturned on, the operation of the internal voltage generating circuit 70 bis stopped and an output of the internal voltage generating circuit 70 bis fixed to the ground level. In this regard, the internal voltagegenerating circuit 70 b is identical to that of the internal voltagegenerating circuit 70 d shown in FIG. 6.

There are no particular constraints on the circuit configurations of theinternal voltage generating circuits 70 b to 70 d as long as theiractivation or inactivation is controlled based on the correspondingunused chip signal DEF. However, as described in examples shown in FIGS.6 and 7, it is preferable to fix the output of the internal voltagegenerating circuits 70 b to 70 d to the ground level when the unusedchip signal DEF is active. By fixing the output of the internal voltagegenerating circuits 70 b to 70 d, the leakage current in variouscircuits using the relevant internal voltages can be reduced.

FIG. 8 is a waveform diagram showing an example of variations in theinternal voltage when the power is turned on in a case where the corechips CC5 and CC7 are defective.

In this example, because the core chips CC5 and CC7 are defective, thecorresponding unused chip signals DEF5 and DEF7 change to a high levelwhen the external voltage VDD is applied. The rest of the unused chipsignals DEF0 to DEF4 and DEF6 are maintained at a low level. Thus, theinternal voltage VPERI is not generated in the core chips CC5 and CC7and their output levels are fixed to the ground. The internal voltageVPERI is properly generated in the rest of the core chips CC0 to CC4 andCC6. However, because the internal voltage generating circuit 70 a isactivated in all the core chips CC0 to CC7 including the defective corechips CC5 and CC7, the internal voltage VPERIa, which is supplied to thelayer address generating circuit 46 and the buffer B3, is properlygenerated in all the core chips CC0 to CC7.

In this manner, in the present embodiment, the internal voltagegenerating circuits 70 b to 70 d are inactivated in the unused corechips among the core chips CC0 to CC7. Therefore, not only the powerconsumption by the internal voltage generating circuits 70 b to 70 d isreduced but the leakage current in the various circuits using theinternal voltages that are the output of the internal voltage generatingcircuits 70 b to 70 d can be also reduced.

There has been explained a case where defective core chips are treatedas unused chips; however, unused chips do not always need to bedefective chips, and normal chips can be intentionally treated as unusedchips. A case where normal chips are treated as unused chips isexplained below.

FIG. 9 is a diagram showing circuits related to selection of the corechips CC0 to CC7. FIG. 10 is a circuit diagram showing an example of aconfiguration of the layer address generating circuit 46.

As shown in FIG. 9, the layer address generating circuit (a chip addressgenerating circuit) 46 is provided in each of the core chips CC0 to CC7and they are cascade connected via the through silicon via TSV2 of thetype shown in FIG. 2B. The layer address generating circuit 46 includesa layer address output circuit 46 a, an incrementing circuit 46 b, and atransfer circuit 46 c.

As shown in FIG. 10, the layer address output circuit 46 a is a logiccircuit that outputs a 3-bit layer address (a chip identificationnumber) LID. When a power-on reset signal PON that is supplied from thepower-on detection circuit 71 shown in FIG. 4 is at a high level, thelayer address output circuit 46 a is reset and the chip identificationnumber of all the core chips is reset to (0, 0, 0). Thereafter, when thepower-on reset signal PON returns to a low level, a layer address LID(B2, B1, B0), which is a first chip address, is obtained from outside.In the present embodiment, the layer address LID (B2, B1, B0) issupplied from the core chip of an immediate upper layer. However,because there is no core chip above the core chip CC0 of the uppermostlayer, a layer address input terminal of the core chip CC0 of theuppermost layer is open.

The layer address output circuit 46 a also receives a count enablesignal COUNTE. The count enable signal COUNTE of the core chip CC0 ofthe uppermost layer is set to a low level (open) and count enablesignals COUNTE of the core chips of the other layers are set to a highlevel (VPERI). Thus, in case of the core chip CC0 of the uppermostlayer, (0, 0, 0) is forcibly output due to the count enable signalCOUNTE input into a NAND gate in the layer address output circuit 46 airrespective of a value of the layer address LID (B2, B1, B0) fromoutside. Furthermore, in case of the other layers, the same value of thelayer address LID (B2, B1, B0) from outside passes through the NAND gatein the layer address output circuit 46 a. Thus, a layer address LID(BC0, BC1, BC2) output from the layer address output circuit 46 a isadopted as a layer address (a second chip address) of its own core chip,and it is supplied to the layer address comparing circuit 47.

Next, the incrementing circuit 46 b outputs an incremented value of thelayer address LID (BC2, BC1, BC0) of its own core chip. The incrementingcircuit 46 b of the core chip CC0 of the uppermost layer generates anincremented value (0, 0, 1) of the layer address LID (0, 0, 0) set inthe layer address output circuit 46 a, and the transfer circuit 46 ctransfers the value (S0, S1, S2) to the core chip CC1 of the lowerlayer. The transferred layer address LID (0, 0, 1) is adopted as a layeraddress of the core chip CC1.

Even in the core chip CC1, an incremented value (0, 1, 0) of the layeraddress LID (0, 0, 1) that is set in the layer address output circuit 46a and incremented by the incrementing circuit 46 b is generated, and thegenerated incremented value (0, 1, 0) is transferred to the core chipCC2 of the lower layer by the transfer circuit 46 c.

Similarly, incremented layer addresses LID are sequentially transferredto the core chips of the lower layers. As a result, finally, a maximumvalue (1, 1, 1) is set as a layer address LID in the layer addressoutput circuit 46 a of the lowermost core chip CC7. With this operation,a unique layer address LID is set for each of the core chips CC0 to CC7.

In the above explanations, it is assumed that all the core chips arenormally functioning. However, when there is a defective chip, it isnecessary to obtain a so-called partial product in which a usage of thedefective chips is stopped and the normal core chips are relieved.Setting of layer addresses in a case when there is a defective chip isexplained below.

As shown in FIG. 9, the layer address generating circuit 46 receives theunused chip signal DEF from the unused chip information holding circuit33 included in the interface chip IF via the through silicon via TSV3 ofthe type shown in FIG. 2C. The unused chip signal DEF is an 8-bit signaland each bit is supplied to respective corresponding core chips CC0 toCC7. The core chip whose corresponding bit of the unused chip signal DEFis active is a defective chip or it is a chip that is intentionally notused in combination with a defective chip.

As described above, in the core chip whose corresponding bit of theunused chip signal DEF is not active, the transfer circuit 46 ctransfers the incremented layer address LID to the core chip of thelower layer. Thus, as shown in FIG. 11, when none of the bits of theunused chip signal DEF are inactive, layer addresses (0, 0, 0) to (1,1, 1) are sequentially allocated to the core chips CC0 to CC7 from theuppermost layer to the lowermost layer.

On the other hand, the transfer circuit 46 c of the core chip whosecorresponding bit of the unused chip signal DEF is active transfers tothe core chip of the lower layer the non-incremented layer address LIDinstead of the incremented layer address LID. Therefore, allocation ofthe layer address LTD relative to the unused core chip is skipped andthe same layer address LID as that of the core chip of the lower layeris allocated to the unused chip. That is, the layer address LIDallocated to each of the core chips CC0 to CC7 is not a fixed addressbut it is changed according to the unused chip signal DEF. The samelayer address LID as that of the core chip of the lower layer isallocated to the unused chip. However, because the control logic circuit63 cannot be activated in the unused chip, a read operation and a writeoperation cannot be performed even if address signals and commandsignals are input from the interface chip IF.

The defective chips that are not operating normally are obviouslyselected as the unused chips. However, some of the normally functioningchips operating normally are selected as unused chips due to addresscontrol. Specifically, by changing the layer address to two bits insteadof changing it to three bits thereby making one layer address selectionline among the three layer address selection lines as unused, the layeraddress control is made easier. In this case, the semiconductor device10 according to the present embodiment can be provided as a partialproduct of 4 GB.

For example, when the core chip CC0 of the uppermost layer (the firstlayer) is defective, and in addition, the core chips CC1 to CC3 of thesecond to fourth layers are selected as the unused chips, as shown inFIG. 12, the layer address LID of all the core chips CC0 to CC4 of thefirst to fifth layers is (0, 0, 0). Furthermore, the layer addresses (0,0, 1) to (0, 1, 1) are sequentially allocated to the core chips CC5 toCC7 of the sixth to eighth layers.

Meanwhile, when the core chip CC0 of the uppermost layer (the firstlayer) and the core chip CC3 of the fourth layer are defective, and inaddition, the core chip CC5 of the sixth layer and the core chip CC7 ofthe eighth layer are selected as unused chips, as shown in FIG. 13, thelayer address LID of the core chip CC0 of the uppermost layer and thecore chip CC1 of the second layer is (0, 0, 0), the layer address LID ofthe core chip CC2 of the third layer is (0, 0, 1), the layer address LIDof the core chip CC3 of the fourth layer and the core chip CC4 of thefifth layer is (0, 1, 0), the layer address LID of the core chip CC5 ofthe sixth layer and the core chip CC6 of the seventh layer is (0, 1, 1),and the layer address LID of the core chip CC7 of the eighth layer is(1, 0, 0).

It can be freely decided as to which of the core chips among the normalcore chips are selected as unused chips. However, some preferreddetermination methods are presumed. In one such method, in view of arelief efficiency of the through silicon via TSV or a resistance of thethrough silicon via TSV, unused chips are selected in sequence from thecore chip CC that is farthermost from the interface chip IF. Forexample, when any one of the core chips CC0 to CC3 of the first tofourth layers is defective, all the core chips CC0 to CC3, including thedefective chip, of the first to fourth layers are selected as unusedchips. Moreover, when any one of the core chips CC4 to CC7 of the fifthto eight layers is defective, in addition to this defective chip, thecore chips CC0 to CC2 of the first to third layers are selected asunused chips. In another method, an unused chip is inserted between usedchips to ensure that the unused chips are not stacked in succession. Forexample, when one of the eight core chips is defective and it isarranged on an even layer, all the core chips on even layers areselected as unused chips and all the core chips on odd layers areselected as used chips. Therefore, a distance between the activatedchips increases and rise in chip temperature can be restrained.Meanwhile, the methods described above can be used in combination.

The layer address LID set as described above is supplied to the layeraddress comparing circuit (a chip address comparison circuit) 47corresponding to each of the core chips CC0 to CC7. The layer addresscomparing circuit 47 is a circuit that compares the layer address LID(the chip identification number) supplied from the layer addressgenerating circuit 46 with the portion of the address signal (the chipselection information) SEL supplied from the interface chip IF via thethrough silicon via TSV. Because the address signal is commonly suppliedto all the core chips CC0 to CC7 via the through silicon via TSV1 of thetype shown in FIG. 2A, the layer address comparing circuit 47 detectsonly one matching core chip.

FIG. 14 is a circuit diagram showing a configuration of the layeraddress comparing circuit 47.

As shown in FIG. 14, the layer address comparing circuit 47 receiveseach bit (A2, A1, A0) of the chip selection information SEL and each bit(BC2, BC1, BC0) of the layer address LID. The layer address comparingcircuit 47 includes ENOR gate circuits G0 to G2 that, respectively,compare corresponding bits of the output signals, and an AND gatecircuit G3 that receives output signals COMP0 to COMP2 of the ENOR gatecircuits G0 to G2. An output of the AND gate circuit G3 is used as acoincidence signal HIT.

When the partial product is used in which four chips are unused chips, apartial signal PER commonly supplied to the core chips CC0 to CC7 isactivated to a high level. The partial signal PER as well as the outputsignal COMP2 are input into an OR gate circuit (a partial gate) G4. Onthe other hand, the output signal COMP2 of the ENOR gate circuit G2 thatcompares the first bit of the layer address is supplied to the AND gatecircuit G3 via the OR gate circuit G4. When the partial signal PER isactive, an output of the OR gate circuit G4 is always maintained at ahigh level irrespective of the output of the ENOR gate circuit G2. Thatis, the layer address comparing circuit 47 that receives the partialsignal PER invalidates the first bit and handles only next two bits forcomparison.

To the layer address comparing circuit 47 of the core chip selected asthe unused chip is supplied the unused chip signal DEF from the unusedchip information holding circuit 33. The unused chip signal. DEF is thesame as that supplied to the layer address generating circuit 46 withinthe same core chip. The AND gate circuit G3 of the layer addresscomparing circuit 47 receives the unused chip signal DEF along with theoutput signals COMP0 to COMP2. Thus, even if the chip selectioninformation SEL matches with each bit of the layer address LID, a signal/DEF supplied to the AND gate circuit G3 via an inverter INV1 ismaintained at a low level when the unused chip signal DEF is highlyactive. Therefore, the coincidence signal HIT is not output.

When all the eight core chips CC0 to CC7 are normally functioning,because all the layer addresses are used, the unused chip signal DEF andthe partial signal PER are not supplied to any of the core chips CC0 toCC7. Thus, all layer address signal lines are activated and all the bitsof the 3-bit layer address become the target of comparison.

When one of the eight core chips CC0 to CC7 is defective, the first bitof the layer address is cut off to make it a half address space and thepackage is used as the so-called partial product. In this case, the fourcore chips including the defective chip are selected as the unused chipsand the unused chip signal DEF is supplied to the selected core chips.Because the remaining four chips are used as normal chips, the unusedchip signal DEF is not supplied to them. In case of the partial product,the partial signal PER is supplied to all the core chips CC0 to CC7.

In the embodiment described above, it has been assumed that the numberof defective chips is less than five. This is because the core chips aretested before assembly, and therefore a possibility of occurrence ofdefect in five or more chips after assembly is considerably low.However, the present invention is applicable even when the number ofdefective core chips is five or more. When five or six defective chipsare to be handled, it is necessary to cut off the first two bits of thelayer address. Therefore, one fourth address space (a portion equivalentto two core chips) can be secured by arranging two partial gatecircuits. Furthermore, when seven core chips are defective, it isnecessary to cut off all the three bits. Therefore, one eighth addressspace (a portion equivalent to one core chip) can be secured byarranging three partial gate circuits.

As described above, in the semiconductor device 10 according to thepresent embodiment, because the unused chip is skipped while allocatingthe layer address LID, the unused chip does not exist from theperspective of a controller. Thus, even if the defective chip isdetected after assembly, only the normal core chips can be operatedwithout having to make a request to the controller for a specificcontrol.

Furthermore, in the present embodiment, if the defective chip isdetected after assembly, the normal chips are also invalidated as perthe requirement and because the number of valid core chips is consideredas a power of two, the address space can be considered as a power oftwo. Therefore, the controller can easily control the layer addresses.Specifically, when the number of defective chips is one to four, thenumber of valid core chips can be four, when the number of defectivechips is five to six, the number of valid core chips can be two, andwhen the number of defective chips is seven, the number of valid corechips can be one.

It is apparent that the present invention is not limited to the aboveembodiments, but may be modified and changed without departing from thescope and spirit of the invention.

For example, in the above embodiment, a DDR3 SDRAM is used as aplurality of core chips each of which has the same functions; however,the present invention is not limited thereto. Accordingly, the presentinvention can be also applied to DRAMs other than a DDR3 DRAM, and canbe a semiconductor memory other than a DRAM, such as an SRAM (StaticRandom Access Memory), a PRAM (Phase Change Random Access Memory), anMRAM (Magnetic Random Access Memory), and a flash memory. In addition,these core chips can be a plurality of semiconductor chips with whichfunctions other than that as a semiconductor memory are identical toeach other or different from each other. That is, these core chips canbe a semiconductor device such as a CPU (Central Processing Unit), anMCU (Micro Control Unit), a DSP (Digital Signal Processor), an ASIC(Application Specific Integrated Circuit), and an ASSP (ApplicationSpecific Standard Circuit). Furthermore, it is not necessary to stackall the core chips, and a part or all of the core chips can be arrangedin a plane. Further, the number of core chips is not limited to eight.

In the embodiment described above, it has been exemplified that the chipidentification number of the uppermost layer is (0, 0, 0) and it isincremented from the uppermost layer toward the lower layers. However,the present invention is not limited thereto, and the chipidentification number of the lowermost layer can be (0, 0, 0) and it canbe incremented from the lowermost layer toward the upper layers.Furthermore, the chip identification number can be decremented insteadof incremented.

Further, the application of the present invention is not limited to achip-stacked semiconductor device. Therefore, for example, as shown inFIG. 15A, in a semiconductor system 200 including a memory controller210 and a memory module 220, an unused chip information holding circuitis provided in the memory controller 210. Thus, some of a plurality ofmemory chips 230 mounted on the memory module 220 can be selected asunused chips. Moreover, as shown in FIG. 15B, in a semiconductor system300 having a CPU 31.0 and a plurality of cache memories 320 mounted onthe same package, an unused chip information holding circuit is providedin the CPU 310. Thus, some of the cache memories 320 can be selected asunused.

What is claimed is:
 1. A method for controlling power in a plurality ofstacked semiconductor devices interconnected by through electrodes,comprising the steps of: receiving an unused chip signal in each of theplurality of stacked semiconductor devices through one or more throughelectrodes; enabling an internal voltage generating circuit in each ofthe plurality of stacked semiconductor devices if the correspondingunused chip signal has a first logic level; and disabling the internalvoltage generating circuit in each of the plurality of stackedsemiconductor devices if the corresponding unused chip signal has asecond logic level not equal to the first logic level.
 2. The method asclaimed in claim 1 wherein each unused chip signal is received through adedicated through electrode.
 3. The method as claimed in claim 2 whereinthe unused chip signals are received through shifted through electrodes.4. The method as claimed in claim 1 wherein the unused chip signals areprovided by an interface chip stacked together with the plurality ofstacked semiconductor devices.
 5. The method as claimed in claim 4wherein the unused chip signals are provided by an unused chipinformation holding circuit on the interface chip.
 6. The method asclaimed in claim 5 wherein the unused chip information holding circuitcomprises a plurality of fuses.
 7. The method as claimed in claim 6wherein unused chip information is written to the fuses during anoperation test after assembly of the plurality of stacked semiconductordevices.
 8. The method as claimed in claim 1 wherein the internalvoltage generating circuit provides an internal voltage higher than anexternal power supply potential.
 9. The method as claimed in claim 1wherein the internal voltage generating circuit provides an internalvoltage lower than an external power supply potential.
 10. The method asclaimed in claim 1 wherein the internal voltage generating circuitprovides a plurality of internal voltages.
 11. The method as claimed inclaim 1 wherein the plurality of stacked semiconductor devices arememory devices.
 12. The method as claimed in claim 1 wherein theplurality of stacked semiconductor devices are dynamic random accessmemory devices.
 13. A system comprising: a plurality of stackedsemiconductor devices interconnected by through electrodes, each of thestacked semiconductor devices being configured to: receive an unusedchip signal through one or more of the through electrodes; enable aninternal voltage generating circuit if the corresponding unused chipsignal has a first logic level; and disable an internal voltagegenerating circuit if the corresponding unused chip signal has a secondlogic level that is not equal to the first logic level.
 14. The systemas claimed in claim 13 wherein each of the plurality of stackedsemiconductor devices is configured to receive the unused chip signalthrough a dedicated through electrode.
 15. The system as claimed inclaim 14 wherein the plurality of stacked semiconductor devices areconfigured to receive the unused chip signals through shifted throughelectrodes.
 16. The system as claimed in claim 13 wherein the systemcomprises an interface chip stacked together with the plurality ofstacked semiconductor devices, the interface chip being configured toprovide the unused chip signals.
 17. The system as claimed in claim 16wherein the interface chip comprises an unused chip information holdingcircuit, the unused chip information holding circuit being configured toprovide the unused chip signals.
 18. The system as claimed in claim 17wherein the unused chip information holding circuit comprises aplurality of fuses.
 19. The system as claimed in claim 18 wherein theinterface chip is configured to write the unused chip information to thefuses during an operation test performed after assembly of the pluralityof stacked semiconductor devices.
 20. The system as claimed in claim 13wherein the internal voltage generating circuit is configured to providean internal voltage higher than an external power supply potential. 21.The system as claimed in claim 13 wherein the internal voltagegenerating circuit is configured to provide an internal voltage lowerthan an external power supply potential.
 22. The system as claimed inclaim 13 wherein the internal voltage generating circuit is configuredto provide a plurality of internal voltages.
 23. The system as claimedin claim 13 wherein the plurality of stacked semiconductor devices arememory devices.
 24. The system as claimed in claim 13 wherein theplurality of stacked semiconductor devices are dynamic random accessmemory devices.